ELEMENTS WHICH REDUCE VALUE Bt 
While not endeavoring to set up a rule for the determination 
of the extent to which it may be proper to take future require- 
ments into account in planning any installation, attention is 
called to the fact that any such provision for anticipated future 
service adds to the investment of capital and thereby makes 
higher earnings necessary than would be required, if, at all 
times, the plant capacity could be kept exactly at the momen- 
tary requirement. Here then is an additional call upon the 
rate-payers, which, naturally, will fall heaviest upon those of 
the early years, at which time the disparity between actual 
demand and the provided capacity is generally greatest. There 
lies herein a further reason why the rate-payer in the early years 
of the life of any public utility should be relieved, as elsewhere 
suggested, of the requirement to meet amortization of capital. 
These rate-payers will ordinarily have done their full share if 
they contribute operating expenses, interest on the investment, 
and whatever may be necessary to anticipate and to meet re- 
placements of discarded parts as such replacements become 
necessary. 
Property not in Use. — Guided by the decisions of the courts 
and by the rulings of public service boards and commissions, 
it has become customary to discriminate with care between the 
property of a public utility which is in use and the property 
which may not strictly be regarded as in use. Property which 
is in no way related to the service rendered and which is of no 
prospective necessity will be left out of consideration in this 
discussion. But there is another type of property owned, but 
not in use, as for example a reservoir site, acquired by a water 
works owner at a favorable moment but not likely to be made 
a part of the system for an indefinite period, or a terminal right 
of way for a railroad, or an undeveloped water-power which 
according to sound judgment must be regarded as necessary for 
future expansion though not in active use as a part of the 
present system. The wisdom of early acquisition of such prop- 
erties at opportune moments can hardly be questioned. How 
to deal with them in making an appraisal for rate-fixing purposes 
8.